The present invention disclosed herein relates to a transistor structure, and more particularly, to a self aligned field effect transistor structure having a self aligned gate electrode and source/drain.
Generally, a semiconductor device and a display device may include various kinds of self aligned field effect transistor structures as a switching device. For example, the semiconductor device may use a Complementary Metal Oxide Semiconductor (CMOS) transistor as a switching device. The display device may use a Thin Film Transistor (TFT) as a switching device. Among the TFTs, a TFT where polysilicon is used for an active layer may operate at a high speed because carriers transfer fast. Accordingly, a polysilicon TFT may be used for a CMOS-TFT, an Erasable and Programmable Read Only Memory (EPROM), an Electrically Erasable and Programmable Read Only Memory (EEPROM), and a Random Access Memory (RAM).